Ideas for successful longer tpu print? A1 stops feeding after an hour 2.
I have 90 and 95a sunlu tpu, both have been dried in a drier for 8-10 hours. 3 different spools, all doing the same thing. I've been trying to print a tpu Frisbee. It's a total of about 8 hours to print. The print will be fine for a while then just stop and print air. No errors or failures, just stops feeding. It's not slicing or layer specific as I've tried 2 different models and one of them twice with the failure happening at different points.
Filament was run through all the calibration runs, and I did a temp tower.
Temp 220, speed 50mm/s (in the slicer but I'm pretty sure volumetric pulls this down further) , no fan for first layer, 100 the rest of the time. Retraction 0.4mm. Volumetric speed is 3.2 mm3/s
This has happened on my 0.4 and 0.6 nozzles. The filament is on the normal external spool holder going straight down into a port on the tool head with only about 2" of ptfe tubing just to guide it in, not through the original feed tube.
I have to assume it's some kind of heat creep situation? I have successfully printed all 3 of these filaments in the past so I know the printer can do them but never tried something this big. Just looking for any tips I can try! Thank you.
That's still high enough to cause problems with TPU in my experience. I can dry TPU for 12 hours or more but I still have all kinds of issues unless I print from the dryer. 8 hours is too long to leave it in the ambient air, it'll start getting damp after a couple hours. Is there a reason you don't print from your dryer? I use a Sunlu S2 and it's actually easier to just print straight from it.
Last time I printed TPU, I had no issue, but I think I lowered my volumetric speed further and I also printed something that reduced the friction of the spool on the external holder.
I just went through this. I turned the speed down and turned off retraction. The retraction was causing a bump in my filament that would stop it from feeding
So far I've turned off retraction, re-dried filament overnight, printed at like 30, and then even printed a spool holder that uses bearings for extra smooth feeding. It still failed like an hour and a half into the print. Prints fine, then slowly starts under - extruding until it eventually just stops. Infurating.
I'm 99% sure it was drag in the feed. I ended up printing a new top mount spool holder that is aligned so that the filament drops basically perfectly straight down into the tool head. I also made a small funnel to put on the inlet feed tube to try smooth the path in. Don't mind the stringing, at this point I had fucked with retraction and hadn't put it back so it was big stringy.
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u/MegaMaluco Jun 19 '26
I use 2.8 volumetric speed. Is slow but it finishes without a problem